Heat fusible poly(vinyl acetate) dispersions

ABSTRACT

It has been discovered that pastes of particulate, thermoplastic, poly(vinyl acetate) type polymers dispersed in a soft resinous phase can be prepared which heat-set by fusion of the thermoplastic binder. When pigmented or otherwise colored, these formulations have utility as printing inks. When uncolored, they can be used as clear overprint coatings. In addition, these fusible pastes have utility as specialty coatings in adhesives and can be fabricated into self-supporting shapes.

BACKGROUND OF THE INVENTION

Printing processes require that printing inks be both fluid and capableof subsequent ready conversion to a dry, smudge-resistant film once inplace on paper or another substrate. One common type of printing inkconsists primarily of a pigment and a binder which are suspended ordissolved in a volatile diluent. The binder serves the purpose ofadhering the pigment to the printed substrate. The diluent mustsubsequently be removed by allowing it to evaporate either at roomtemperature, or for higher printing speeds, by heating. Large amounts ofheat are needed to vaporize the ink diluent, which requires thatsubstantial quantities of fuel be consumed. Since large volumes of airmust be drawn over the drying ink film to remove the diluent vapor,frequently much heat is wasted. Further, the evaporation of the inkdiluent into the open atmosphere can be a source of pollution. In manyinstances, it is necessary or desirable to burn off or otherwise removethe solvent vapor from the drying air before discharging it to theatmosphere. Additional fuel is consumed and special equipment must beinstalled for this purpose.

A second common type of printing ink consists of mixtures containingoleoresinous varnishes and/or drying oils which set by air oxidation.These inks set slowly so it is necessary to take precautions to avoidset-off (transfer) of ink between printed sheets.

Inks may also be formulated which contain drying oils or the liketogether with some binder and volatile diluent. In the usual printingoperation, heat is applied to such an ink immediately after it isprinted onto the substrate. At this stage, the diluent is driven off,reducing or minimizing problems of ink set-off. However, the ink is notfully set and rub resistance is inadequate. A subsequent drying stage isnecessary in which the drying oil or the like hardens, as by oxidationand/or polymerization.

While it is necessary that a printing ink set rapidly and convenientlyafter printing, it is equally necessary that it not set or dry on thepress. Inks containing volatile components may thicken on the press asthe solvent evaporates, making it difficult or impossible to control theprinting process. Air oxidizing varnishes, drying oils, and the like,may thicken or gum on the press on exposure to the atmosphere. Such inksare especially inclined to "skin over" when the press is shut downduring a run. An ink which is not subject to such changes while on theprinting press is said to "stay open".

Ink technologists have sought to achieve inks which set rapidly with alow level of energy input to initate setting, which do not releasepolluting materials to the atmosphere, and which stay open on the press,while at the same time meeting the physical and mechanical requirementsof the printing process. Much attention has been directed to highlychemically reactive formulations. After printing, such inks are set bypolymerization and/or crosslinking which is initiated by heat orradiation. A typical chemically reactive system contains polyfunctionalacrylate esters (often in combination with other unsaturated materials),one or more ultraviolet photoinitiators, pigment and a variety ofsecondary components to control ink physical properties. See U.S. Pat.No. 3,804,640 and U.S. Pat. No. 3,881,942, both to Buckwalter. In normaluse, such inks are printed on presses equipped with ultraviolet lampswhich expose the film on the paper or other substrate immediately afterprinting. The inks set rapidly and with essentially no emission ofpolluting materials. Inks based on such highly reactive materials,however, have limited storage stability. The acrylates and otherreactive materials in common use have been found to be chemicallyincompatible with some pigments which are desirable in printing inks.They present toxicity hazards, or are dangerous eye irritants, and arefrequently skin sensitizers. When the inks are designed to be set by anultraviolet light initiated reaction, the ultraviolet radiation itselfand the high voltages necessary to power the ultraviolet lamps areadditional health and safety hazards.

U.S. Pat. No. 3,024,213 to Ludlow discloses a heat drying ink vehiclebased on poly(vinyl chloride) plastisols, more particularly finelydivided poly(vinyl chloride) polymer dispersed in liquid plasticizers,all of which have low viscosity and solubility parameters closelymatched to poly(vinyl chloride), and containing a compatiblethermoplastic resinous binder to increase ink cohesion and tack. Furtherimprovements in inks based on poly(vinyl chloride) and vinyl chloridecopolymer plastisols are disclosed in U.S. Pat. No. 3,760,724 toBudzinski. These inks are set by applying heat which causes the liquidplasticizers and poly(vinyl chloride) or vinyl chloride copolymer toco-dissolve. Thus, such poly(vinyl chloride) plastisol-based inks arereadily heat-settable without significant release of volatile materialsto the atmosphere. These inks, however, do not have good press runningcharacteristics. Undesirable build-up of material on the blanket oflithographic offset presses occurs when poly(vinyl chloride) plastisolinks are used. Further, both Ludlow and Budzinski require the use of atleast one plasticizer in such poly(vinyl chloride) ptastisol inks. Suchplasticizers may, as Ludlow discloses, damage ordinary natural rubberrolls on printing presses. It is thus necessary that ink rolls ofpolyurethane rubber or other plasticizer resistant compositions be used.

SUMMARY OF THE INVENTION

The present invention provides nonvolatile, heat-set pastes. It has beendiscovered that pastes of particulate, glassy thermoplastic poly(vinylacetate) type polymers dispersed in a soft resinous phase can beprepared which heat-set by the fusion of the poly(vinyl acetate) binder.When pigmented or otherwise colored, these formulations have utility asprinting inks. When uncolored, they can be used as clear over-printcoatings. In addition, these fusible pastes have utility as specialtycoatings and adhesives and can be fabricated into self-supportingshapes.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

According to this invention, nonvolatile, heat-set vehicles for printinginks can be made by dispersing particulate, poly(vinyl acetate) typepolymer binders in a soft resinous phase. More particularly, theprinting ink vehicles of this invention contain particulate, poly(vinylacetate) type polymers dispersed in a tackifying, cohesion-increasingmaterial which may be a resin or mixture of resins whose softening pointis either at or below room temperature, or has been lowered by dilutionwith an oil.

The binder materials used in this invention comprise particulate, glassythermoplastic poly(vinyl acetate) type polymers with a molecular weightabove about 50,000.

While the particle size of the binder is not critical, for lithographicor letterpress inks particles about 0.05 to about 2.0 microns incross-section are preferred, with particles of about 0.1 to 0.5 micronin cross-section being most preferable. Larger particles may give pooruniformity and press performance. In screen printing, much heavier inkfilms are printed, so much larger particle sizes may be tolerated. Thelimit in particle size for inks used in screen printing is fixed by themesh size of the printing screen and the thickness of the ink filmdesired. For use with coarse mesh screens and heavy ink films, particlesizes as high as about 50 microns can be used.

The poly(vinyl acetate) type polymers used in the pastes of thisinvention are based on vinyl acetate, either alone or in combinationwith one or more comonomers, with at least 60% of the monomers beingvinyl acetate. Comonomers with the vinyl acetate monomer may include oneor more addition polymerizable compounds such as other vinyl esters,including vinyl formate, vinyl propionate, vinyl stearate and vinylbenzoate; the saturated esters of ethylenically unsaturated carboxylicacids, including acrylate-type monomers, which class is here taken toinclude acrylates, methacrylates, acrylonitrile and methacrylonitrile,including methyl methacrylate, ethyl methacrylate, butyl methacrylate,isobutyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate,and the like; and vinyl and vinylidene halides, including vinyl chlorideand vinylidene chloride.

Other comonomers may be included if they do not interfere with theoperation of the invention. It may be desirable to include certainadditional polymer components to facilitate the preparation of particlesof appropriate size. Such monomers may include ethylenically unsaturatedcarboxylic acids which may be mono- or polycarboxylic acids such asacrylic acid, methacrylic acid, itaconic acid, fumaric acid, maleic acidand anhydride, citraconic acid and anhydride and other such acids.

Thermoplastic poly(vinyl acetate) type polymer particles of a sizeuseful in this invention can be conveniently obtained by evaporating thediluent from emulsion or dispersion polymerized systems, as described inDispersion Polymerization In Organic Media, edited by K. E. J. Barrett(John Wiley & Sons, N.Y., 1975). For materials with glass transitiontemperatures below about 50° C., it may be desirable to add some portionof the soft resin phase of the paste to the polymer dispersion beforeevaporating the polymerization diluent. Alternatively, particles may beprepared by grinding or milling the polymers, by controlledprecipitation from solution. In many cases, a particle sizeclassification process may be necessary to obtain the optimum size ofthe material.

The continuous soft resinous phase of the paste is comprised of atackifying, cohesion-increasing material which may be a resin or mixtureof resins with a softening point at or below room temperature, or whichhas been diluted with an oil to suitably lower the softening point. Theterm "resin" is here restricted to amorphous organic solids, semi-solidsand viscous liquids with room temperature viscosities above about 2000centipoise. Such resins are commonly polymeric, but number averagemolecular weight must be under about 5000. Typical classes of resinswhich may be used are hydrocarbon resins, including naturally occurringcoal tar and other fossil resins, synthetic aliphatic and aromatichydrocarbon resins prepared from petroleum- or coal-derived feedstocks,and resins based on pure hydrocarbon monomers and combination ofmonomers, such as styrene and alkyl-substituted styrenes, indene anddicyclopentadiene; terpene resins; rosin and rosin esters such ashydrogenated methyl ester of rosin and phenolic modified pentaerythritolester of rosin; ketone formaldehyde thermoplastic resins; condensedketone thermoplastic resins; and resins based on acrylate esters andalkyl-substituted acrylate esters; and transesterification products ofalcohols with dimethyl terephthalate process residues.

Diluent oils may be aliphatic, aromatic or naphthenic in character, andmay contain polar functionality, but must be compatible with anddissolve in the resin system. Typically, they have solubility parametersbetween about 7.0 and 8.5. They must be substantially nonvolatile at thetemperature at which the ink is set, typically 150° C. or higher. It isimportant to choose diluents which do not rapidly solvate theparticulate thermoplastic phase at room temperature. This may beaccomplished by avoiding those diluent oils which closely match thesolubility parameter of the particulate thermoplastic. Typically, thesolubility parameter midpoint for poly(vinyl acetate) with respect toweakly hydrogen-bonded solvents such as hydrocarbon oils or chlorinatedhydrocarbons is at or about 9.4. Poly(vinyl acetate) is insoluble instrongly hydrogen-bonding solvents. Liquid plasticizers of the sorttypically used to prepare poly(vinyl chloride) plastisols (commonlyreferred to as "primary plasticizers") such as those disclosed by Ludlowin U.S. Pat. No. 3,024,213, have solubility parameters between about 8.5and 11 and are not used in the pastes of this invention.

There is no such restriction on the solubility parameter of the resinitself. The rate of solvation is slow enough that even inks containingresins which closely match the solubility parameter of the particulatethermoplastic may be prepared and run on a press. In extreme cases,solvation may proceed at a rate that would limit certain combinations ofresin and thermoplastic polymers to applications where inks are preparedas needed, and are not stored longer than a day or so. Printing inks arecommonly prepared as needed in larger printing plants. Under suchcircumstances, the chemical composition of the particulate thermoplasticpolymers and the resin may be essentially identical, the materialsdiffering only in physical form and molecular weight.

The poly(vinyl acetate) polymer and soft resin of this invention shouldbe used in proportions such that the ratio of polymer to resin willpreferably be between about 1:6 and about 1:1. Also, the ratio of softresin to diluent oil may range from these cases in which the formulationis oil-free (i.e., where the soft resin is naturally thin enough toachieve the desired rheology in the final fusible paste formulation) toabout a 1:15 ratio of resin to oil.

In addition to the above-described essential ingredients, when thepastes are used as printing inks surface active agents, pigmentdispersing aids, waxes, slip aids, tack modifiers and the like may beincluded.

The primary mechanism by which the pastes of this invention set appearsto be the fusion of the particulate thermoplastic poly(vinyl acetate)binder to form a continuous film on heating the plate, in which the softresinous phase is largely dissolved and/or entrapped. In somecircumstances, it may be desirable for the paste film to harden further.This can be achieved by choosing for the soft resinous phase, either inwhole or part, materials capable of undergoing polymerization orcross-linking during the thermal fusion of the particulate thermoplasticmaterial or subsequent to it. In such cases, it may be appropriate toinclude suitable catalysts, driers, accelerators, or other additiveswhich are necessary or desirable to initiate or promote the desiredpolymerization or cross-linking reaction. Such subsequent hardening ofthe thermally set paste film may be achieved by including one or moreunsaturated alkyd resins as part of the resinous phase, such as alkydsbased on phthalic, isophthalic, adipic, azelaic, sebacic, terephthalic,hydrophthalic, maleic, fumaric, and benzoic acids and anhydridesmodified with unsaturated fatty acids; rosin modified alkyds; phenolicmodified alkyds; epoxy alkyds; polyamide alkyds; isocyanate alkyds; andstyrene or substituted styrene alkyds, such as styrene and acrylonitrilemodified alkyds. The unsaturated isophthalic alkyds are preferred.

Similarly, drying oils or semi-drying oils such as linseed oil, tungoil, oiticica oil, dehydrated castor oil, soya oil, safflower oil, fishoil, tall oil, or the like may be used as hardening agents in theresinous phase. These oils may be used in the natural state or may bebodied to increase viscosity by heating or other partial polymerization.

When such oxidation drying materials are included in the paste, suitabledriers or catalysts which promote oxidative cross-linking andpolymerization may be included, typically salts or complexes of metalscapable of existing in more than one valence state, such as vanadiumoxyacetylacetonate, vanadium oxysulfate, vanadiumoxy-1,1,1-trifluoroacetylacetone, vanadium oxy-1-phenylacetylacetonate,ferric acetylacetonate-benzoin, manganese octoate, lead naphthenate,cobaltic acetylacetonate, titanyl acetylacetonate, cobaltousnaphthenate, cobaltous 2-ethylhexanoate, cobaltous stearate, cobalticstearate, cobaltous acetylacetonate, manganous stearate, manganicstearate, manganous acetylacetonate, manganic acetylacetonate, manganesenaphthenate, zirconium acetylacetonate, vanadyl naphthenate, ferroussulfate, ferrous pyrophosphate, ferrous sulfide, the ferrous complex ofethylenedinitrolotetraacetic acid, ferrous o-phenanthroline, ferrousferrocyanide, ferrous acetylacetonate and the corresponding nickel,copper, mercury and chromium compounds.

The use of a colorant is not critical to the invention. The fusiblepaste dispersions can be used unpigmented as a clear overprint varnish.When a colorant is desired, it may be a pigment or dye. The colorantnormally may be most conveniently dispersed in the continuous softresinous phase of the ink. However, it may be desirable in somecircumstances to include the colorant within the particulatethermoplastic material.

When used as printing inks, the pastes of this invention may be printedby any of the printing processes which require a paste type ink. Commonprinting processes in which paste inks are used include letterpress,lithography, and screen printing. Printing may be sheet-fed or web-fed,and may be on paper, board, fabric, metal, glass, plastic, wood,leather, rubber, or other substrates. Variations in ink rheology andtack properties are required for optimum performance for any chosenprinting process and substrate. Inks based on the pastes of thisinvention can be suitably formulated to meet these specific requirementsby appropriate choice and relative concentration of materials used inthe resinous phase. This will be readily apparent to those skilled inprinting ink formulation.

In addition to printing, pastes may be applied to substrates byroll-coating, doctoring, screening, dipping, or the like, especially forthe preparation of speciality coatings or for use as heat-setthermoplastic adhesives. Self-supporting shapes may be prepared bycavity molding, dip molding, rotational molding, slush molding or thelike. Variations in place rheology and tack properties are required foroptimum performance for any chosen fabrication process. The pastes canbe formulated to meet these requirements by appropriate choice andrelative concentration of materials used in the resinous phase. Thiswill be readily apparent to those skilled in the art of materialsfabrication.

After printing, coating, or forming, the pastes of this invention may beset by heating to at least about 75° C. and preferably to at least about150° C. to fuse the particulate, thermoplastic polymer. This may be donein a conventional forced-air drying oven, in common use in the printingindustry. However, since no air flow is necessary to remove volatilematerial, it is frequently advantageous to heat the paste film byirradiation, typically in the infrared spectral region. At 150° C., thepaste may be fused by heating for from about 0.01 second to about 2minutes, longer times being required for those pastes which do notcontain pigments than for those which do contain pigment. Also, theduration of the heating may vary depending upon the thickness of thepaste coating, substrate, or purpose for which the paste is used (e.g.,adhesive, molding material, etc.).

EXAMPLE 1

Finely divided poly(vinyl acetate) is prepared as follows. A solution isprepared which consists of 223 parts n-heptane, 148 parts n-hexane, 59.3parts vinyl acetate, (VAc) 0.8 grams azobisisobutyronitrile (AIBN) and18.4 parts of poly(lauryl methacrylate-co-glycidyl methacrylate) inwhich 80% of the glycidyl groups had been reacted with methacrylic acid(mole ratio of LMA to GMA=19). The solution is heated to 85° C. for 45minutes and then a solution of 0.8 part AIBN in 337.8 parts VAc is addedover 3 hours while the mixture is held at 80°-85° C. The dispersion thatresults has a solid content of 52.4%, and a particle size of 0.47micron. The PVAc in the dispersion has a molecular weight of 225,000 anda glass transition temperature of 37° C.

One hundred grams of this dispersion is mixed with 52.4 grams of thehydrogenated methyl ester of rosin (Hercolyn D) and the volatilehydrocarbons are removed by distillation under reduced pressure. Theresulting dispersion of PVAc in resin is mixed with a dispersion ofcarbon black in the hydrogenated methyl ester of rosin plus ink varnish.

The final composition is:

    ______________________________________                                        Ingredients            Parts by Weight                                        ______________________________________                                        Poly(vinyl acetate     100                                                    Hydrogenated methyl ester of rosin                                                                   180                                                    with a viscosity of 5800 cps.                                                 Ink varnish-pentaerythritol ester                                                                     60                                                    of dimerized rosin in liquid iso-                                             phthalic alkyl resin in a weight                                              ratio of 1:2 and less than 0.1%                                               volatility at 150° C.                                                  Carbon black            60                                                    ______________________________________                                    

The ink is printed on paper on a lithographic offset press. The printedsheets are passed at about 45 meters/minute under a 100 watt/cm infraredlamp with a peak output of about 1 micron (model 5193-5 line heatermanufactured by Research Incorporated, Minneapolis, Minnesota, operatedat 230 volts) at a distance of 2.5 cm from the lamp reflector edge whichresults in the rapid setting of the ink film. After setting, the ink isdry and resistant to smudging or smearing.

EXAMPLE 2

An ink is prepared as in Example 1 with the following formulation:

    ______________________________________                                        Ingredients            Parts by Weight                                        ______________________________________                                        Poly(vinyl acetate)    100                                                    Hydrocarbon resin - largely aromatic;                                                                160                                                    based on petroleum and coal-derived                                           monomers with a ring and ball soften-                                         ing point of 10° C., and a number                                      average molecular weight below 5000.                                          Ink varnish - phenolic-modified                                                                      100                                                    pentaerythritol ester of rosin                                                dissolved in alkali-refined linseed                                           oil with a solubility parameter of about                                      7.8 in a weight ratio of 40:60 and less                                       than 0.1% volatility at 150° C.                                        Carbon black            36                                                    ______________________________________                                    

The ink is printed and set as in Example 1. After setting, the ink isdry and resistant to smudging or smearing.

EXAMPLE 3

An ink is prepared as in Example 1. The final formulation is:

    ______________________________________                                        Ingredients            Parts by Weight                                        ______________________________________                                        Poly(vinyl acetate)    100                                                    Hydrocarbon resin - based principally                                                                160                                                    on alpha-methyl styrene and styrene;                                          ring and ball softening point 25° C.,                                  and with a number average molecular                                           weight below 5000.                                                            Extending oil - petroleum derived;                                                                    80                                                    solubility parameter about 7.8;                                               less than 0.1% volatility at 150° C.                                   Carbon black            34                                                    ______________________________________                                    

The ink is printed and set as in Example 1. After setting, the ink isdry and resistant to smudging and smearing.

EXAMPLE 4

An ink is prepared as in Example 1 with the following formulation:

    ______________________________________                                        Ingredients            Parts by Weight                                        ______________________________________                                        Poly(vinyl acetate)    100                                                    Hydrocarbon resin - largely aliphatic;                                                               160                                                    based on petroleum-derived monomers                                           with a ring and ball softening point                                          of 10° C. and a number average molecular                               weight below 5000.                                                            Extending oil - petroleum derived;                                                                    50                                                    solubility parameter about 7.8;                                               less than 0.1% volatility at 150° C.                                   Carbon black            31                                                    ______________________________________                                    

The ink is printed and set as in Example 1. After setting, the ink isdry and resistant to smudging and smearing.

EXAMPLE 5

An ink was prepared as in Example 1 with the following formulation:

    ______________________________________                                        Ingredients            Parts by Weight                                        ______________________________________                                        Poly(vinyl acetate)    100                                                    Methyl ester of rosin with a viscosity                                                               160                                                    of about 2700 centipoise. -Ink varnish - phenolic-modified                                            40                                                    pentaerythritol ester of rosin dissolved                                      in alkali-refined linseed oil with a                                          solubility parameter of about 7.8 in a                                        weight ratio of 40:60 and less than 0.1%                                      volatility at 150° C.                                                  Carbon black            30                                                    ______________________________________                                    

The ink is printed and set as in Example 1. After setting, the ink isdry and resistant to smearing and smudging.

EXAMPLE 6

An ink is prepared as in Example 1 having the following formulation:

    ______________________________________                                        Ingredients            Parts by Weight                                        ______________________________________                                        Poly(vinyl acetate)    100                                                    Hydrocarbon resin - largely aromatic;                                                                160                                                    based on petroleum- and coal-derived                                          monomers with a ring and ball softening                                       point of 10°  C. and a number average                                  molecular weight below 5000.                                                  Ink varnish -phenolic-modified                                                                       100                                                    pentaerythritol ester of rosin dissolved                                      in long oil linseed isophthalic alkyd                                         in a weight ratio of 20:80 and less than -0.1% volatility at 150°      C.                                                                            Carbon black            40                                                    ______________________________________                                    

The ink is printed and set as in Example 1. After setting, the ink isdry and resistant to smudging and smearing.

EXAMPLE 7

An ink is prepared as in Example 1 with the following formulation:

    ______________________________________                                        Ingredients            Parts by Weight                                        ______________________________________                                        Poly(vinyl acetate)    100                                                    Hydrocarbon resin -largely aromatic,                                                                 80                                                     based on petroleum- and coal-derived                                          monomers with a ring and ball softening                                       point of 10° C. and a number average                                   molecular weight below 5000.                                                  Hydrocarbon resin- largely aromatic;                                                                 40                                                     based on petroleum- and coal-derived                                          monomers; a ring and ball softening                                           point of 25° C.                                                        Radiant fluorescent chartreuse pigment                                                               95                                                     (Hercules Incorporated)                                                       ______________________________________                                    

The ink is printed and set as described in Example 1. After setting, theink is dry and resistant to smudging and smearing.

EXAMPLE 8

An ink is prepared as in Example 1 having the following formulation:

    ______________________________________                                        Ingredients            Parts by Weight                                        ______________________________________                                        Poly(vinyl acetate)    100                                                    Hydrocarbon resin -largely aromatic;                                                                 180                                                    based on petroleum- and coal-derived                                          monomers with a ring and ball softening                                       point of 10° C. and a number average                                   molecular weight below 5000.                                                  Extending oil - petroleum derived;  20                                        solubility parameter about 7.8;                                               less than 0.1% volatility at 150° C.                                   Titanium dioxide        15                                                    ______________________________________                                    

The ink is screen printed onto glass and set by oven heating for 2minutes at 135° C. The resulting film is dry and scratch resistant.

EXAMPLE 9

The ink of Example 1 is screen printed onto cotton fabric. The ink isset by IR radiation as in Example 1. The cotton fabric is laundered inan automatic washing machine with a detergent with no loss of image.

EXAMPLE 10

A paste is prepared as in Example 1 with the following formulation:

    ______________________________________                                        Ingredients                 Parts by Weight                                   ______________________________________                                        Poly(vinyl acetate)    120                                                    Hydrocarbon resin - largely aromatic;                                                                160                                                    based on petroleum- and coal-derived                                          monomers with a ring and ball softening                                       point of 10° C. and a number average                                   molecular weight below 5000.                                                  Ink varnish - phenolic-modified                                                                      100                                                    pentaerythritol ester of rosin dissolved                                      in alkali-refined linseed oil with a                                          solubility parameter of about 7.8 in a                                        ratio of 40:60 and less than 0.1%                                             volatility at 150° C.                                                  ______________________________________                                    

The paste is printed as an overprint varnish on a lithographic offsetpress. The printed sheets are heated to 200° C. for 2 minutes in aforced air oven. After setting, the coating is dry and smudge resistant.

EXAMPLE 11

A paste is prepared as in Example 1 with the following formulation:

    ______________________________________                                        Ingredients            Parts by Weight                                        ______________________________________                                        Poly(vinyl acetate)    100                                                    Hydrocarbon resin - largely aromatic;                                                                100                                                    based on petroleum- and coal-derived                                          monomers with a ring and ball softening                                       point of 10°  C. and a number average                                  molecular weight below 5000.                                                  Ink varnish - phenolic-modified                                                                      80                                                     pentaerythritol ester of rosin dissolved                                      in alkali-refined linseed oil with a                                          solubility parameter of about 7.8 in a                                        ratio of 40:60 and less than 0.1%                                             volatility at 150°  C.                                                 Extending oil - petroleum derived;                                                                   20                                                     solubility parameter of about 7.8;                                            less than 0.1% volatility at 150° C.                                   Titanium dioxide       14                                                     ______________________________________                                    

The paste is roll-coated onto paper and heated by passing under an IRlamp, which results in rapid setting of the paste film. After setting,the coating is dry and resistant to smearing.

EXAMPLE 12

A paste is prepared as in Example 1 with the following formulation:

    ______________________________________                                        Ingredients            Parts by Weight                                        ______________________________________                                        Poly(vinyl acetate)    100                                                    Hydrocarbon resin - largely aliphatic;                                                               160                                                    based on petroleum-derived monomers                                           with a ring and ball softening point of                                       10° C. and a number average molecular                                  below 5000.                                                                   ______________________________________                                    

The paste is blade-coated onto a Bonderite 100 treated cold rolled steelpanel. The coated panel is heated for five minutes in a forced-air ovenat 175° C. On cooling, the resulting coating is dry and rub-resistant.

EXAMPLE 13

The paste of Example 12 is doctored onto two pieces of bleached poplin.The coated fabrics are pressed together with an iron at 120° C. forunder one minute. On cooling, a strong fabric-to-fabric bond results.

EXAMPLE 14

The paste of Example 12 is pressed into a metal mold which hadpreviously been coated with a mold release. The filled mold is placed inan oven at 200° C. for 10 minutes. On cooling, the resulting moldedobject is removed from the mold and has accurately replicated the designof the mold cavity.

EXAMPLE 15

An ink is prepared as in Example 1 with the following formulation:

    ______________________________________                                        Ingredients            Parts by Weight                                        ______________________________________                                        Poly(vinyl acetate)    100                                                    Resin-transesterification products of                                                                160                                                    of 2-ethylhexanol with dimethyl                                               terephthalate process residue largely                                         comprising methyl and benzyl esters of                                        biphenyldicarboxylic and tricarboxylic                                        acids with a viscosity above 2000 centi-                                      poise and a number average molecular                                          weight below 5000.                                                            Carbon black            26                                                    ______________________________________                                    

The ink is printed on a lithographic press and on a Van der Cookproofing press and prints are set by passing under an IR lamp asdescribed in Example 1. After setting, the ink is dry andsmudge-resistant.

EXAMPLE 16

A fusible paste ink is prepared with the following composition:

    ______________________________________                                        Ingredients            Parts by Weight                                        ______________________________________                                        Poly(vinyl acetate)    100                                                    Hydrogenated methyl ester of rosin                                                                   240                                                    with a viscosity of about 5500                                                centipoise                                                                    Phenolic-modified pentaerythritol                                                                     20                                                    ester of rosin                                                                Carbon black            40                                                    ______________________________________                                    

The ink is prepared by (1) dissolving the phenolicmodifiedpentaerythritol ester of rosin in the hydrogenated methyl ester ofrosin; (2) dispersing the polystyrene in about two-thirds of the abovesolution on a three-roll mill; (3) dispersing the carbon black in theremaining one-third of the resin solution on a three-roll mill; and (4)blending the two dispersions together with a light mixing pass on athree-roll mill.

The ink is printed on a Little Joe press. Prints are set by placing inan oven at 150° C. for 90 seconds, in an oven at 200° C. for 30 secondsand on a curved hot plate at 288° C. for 3 seconds.

EXAMPLE 17

A paste is prepared as in Example 16 with the omission of the carbonblack. The paste is used as an overprint varnish by printing on asheet-fed lithographic press. The resulting clear coating is set byplacing in an oven at 150° C. for 90 seconds.

EXAMPLE 18

Finely divided vinyl acetate-ethyl acetate copolymer is prepared exactlyas described in Example 1 except that in place of the vinyl acetatethere is used an 85:15 mixture of vinyl acetate and ethyl acrylate. Theresulting dispersion contains 51.4% solids, and has a particle size of0.45 micron. The polymer has a reduced specific viscosity of 1.32determined in chloroform solution at 25° C., which indicates a molecularweight above 100,000, and has a second order transition temperature of19° C.

To 100 parts of the above dispersion are added 51.4 parts of thehydrogenated methyl ester of rosin. After evaporation of volatilediluents, the resulting dispersion is mixed with a dispersion of carbonblack in the hydrogenated methyl ester of rosin and ink varnish to givea composition identical to that of Example 1 except for substitution ofthe polymer component.

The ink is printed and set as in Example 1. After setting, the ink isdry and resistant to smudging or smearing.

EXAMPLE 19

Finely divided vinyl acetate-ethyl acetate copolymer is prepared exactlyas described in Example 1 except that in place of the 59.3 parts vinylacetate there is used a 70:30 mixture of vinyl acetate and ethylacrylate and the post-heating time at 85° C. is three hours. Theresulting dispersion contains 50.8% solids and has a particle size of0.44 micron. The polymer has a reduced specific viscosity of 1.24 whichcorresponds to a molecular weight above 100,000 and has a second ordertransition temperature of 6° C.

To 100 parts of the above dispersion is added 300 parts of thehydrogenated methyl ester of rosin in which is dispersed 50 parts ofcarbon black. After evaporation of volatile diluents, the resulting inkis printed and set as in Example 1. After setting, the ink is dry andresistant to smudging and smearing.

EXAMPLE 20

Finely divided vinyl acetate-methyl methacrylate copolymer is preparedexactly as described in Example 1 except that in place of the vinylacetate there is used a 75:25 mixture of vinyl acetate and methylmethacrylate and the heating temperature is maintained in the range of75° to 85° C. After the postheating period, 60 parts of unreacted vinylacetate is removed by evaporation with about 180 parts of thehydrocarbon solvent so that the ratio of the monomers in the polymer isabout 68:32. The resulting dispersion has a solids content of 52.4% andthe particle size of 0.41 micron. The reduced specific viscosity of thepolymer is 1.54 which corresponds to a molecular weight of approximately217,000. The polymer has a glass transition temperature of 38° C.

To 100 parts of the above dispersion is added 200 parts of thehydrogenated methyl ester of rosin in which is dispersed 25 parts ofcarbon black. After evaporation of the volatile diluents, the resultingink is printed and set as in Example 1. After setting, the ink is dryand resistant to smudging and smearing.

EXAMPLE 21

Finely divided vinyl acetate-ethyl acrylate copolymer is preparedexactly as described in Example 1 except that in place of vinyl acetatethere is used a 60:40 mixture of vinyl acetate and ethyl acrylate. Thepostheating time is extended to 2-1/2 hours at 80° C. followed bydistillation to remove 66.5 parts of a mixture of unreacted monomer andsolvent. The resulting dispersion contains 53.6% solids and has aparticle size of 0.43 micron. The polymer has a reduced specificviscosity of 1.24 which indicates a molecular weight above 100,000 andhas a glass transition temperature of 0° C.

100 parts of this dispersion is mixed with 52.4 parts of thehydrogenated methyl ester of rosin and the volatile hydrocarbons removedby distillation under reduced pressure. The resulting dispersion ismixed with a dispersion of carbon black in the hydrogenated methyl esterof rosin plus ink varnish.

The final composition is:

    ______________________________________                                        Ingredients            Parts by Weight                                        ______________________________________                                        Vinyl acetate--ethyl acrylate                                                                        100                                                    copolymer                                                                     Hydrogenated methyl ester of rosin                                                                   180                                                    with a viscosity of 5800 cps.                                                 Ink varnish - pentaerythritol ester                                                                   60                                                    of dimerized rosin liquid iso-                                                phthalic alkyl resin in a weight                                              ratio of 1:2 and less than 0.1%                                               volatility at 150° C.                                                  Carbon black            60                                                    ______________________________________                                    

The ink is printed on paper on a lithographic offset press as describedin Example 1. After setting, the ink is dry and resistant to smudging orsmearing.

What I claim and desire to protect by Letters Patent is:
 1. Acomposition of matter consisting essentially of (1) discrete solidparticles of a thermoplastic polymeric material, said polymeric materialhaving been prepared from at least 60% of vinyl acetae, saidthermoplastic polymeric material having a particle diameter betweenabout 0.05 micron to about 50 microns, said thermoplastic polymericparticles being dispersed in (2) a tackifying, cohesion-increasingmaterial whose softening point is at or below room temperature, saidpolymeric material and said cohesion-increasing material being presentin said composition in a ratio of polymeric material tocohesion-increasing material of between about 1:6 to about 1:1.
 2. Thecomposition of claim 1 wherein the thermoplastic polymer is poly(vinylacetate).
 3. The composition of claim 1 wherein the tackifying,cohesion-increasing material comprises a resin or mixture of resinswhose softening point is at or below room temperature.
 4. Thecomposition of claim 1 wherein the tackifying, cohesion-increasingmaterial comprises a mixture of at least one resin and at least onediluent oil as a softening point lowering agent, the softening point ofsuch mixture being at or below room temperature.
 5. The composition ofclaim 4 wherein the diluent oil has a solubility parameter between about7.0 to about 8.5.
 6. The composition of claim 1 wherein the tackifying,cohesion-increasing material is selected from a hydrocarbon resin, anester of rosin and mixtures thereof.
 7. The composition of claim 6wherein the hydrocarbon resin is an aromatic hydrocarbon resin.
 8. Thecomposition of claim 6 wherein the ester of rosin is selected from amethyl ester of rosin, hydrogenated, methyl ester of rosin, methyl esterof disproportionated rosin and esters and modified esters of rosin withpolybasic alcohols.
 9. The composition of claim 1 further comprisingcoloring material.
 10. The composition of claim 1 further comprising atleast one hardening agent selected from drying oils and unsaturatedalkyds.
 11. The composition of claim 10 wherein the hardening agent isselected from linseed oil, bodies linseed oil, and long oil isophthalicalkyd.
 12. A printing ink vehicle consisting essentially of (1) discretesolid particles of a thermoplastic polymeric material consisting ofpoly(vinyl acetate) or a copolymer containing at least 60 mole percentvinyl acetate, said thermoplastic polymeric material having a particlediameter between about 0.5 micron and about 50 microns, saidthermoplastic polymeric particles being dispersed in (2) a tackifyingcohesion-increasing material whose softening point is at or below roomtemperature, said polymeric material and said cohesion-increasingmaterial being present in said composition in a ratio of polymericmaterial to cohesion-increasing material of between about 1:6 to about1:1.
 13. An adhesive composition consisting essentially of (1) discretesolid particles of a thermoplastic polymeric material consisting ofpoly(vinyl acetate) or a copolymer containing at least 60 mole percentvinyl acetate, said thermoplastic polymeric material having a particlediameter between about 0.05 micron and about 50 microns, saidthermoplastic polymeric particles being dispersed in (2) a tackifyingcohesion-increasing material whose softening point is at or below roomtemperature, said polymeric material and said cohesion-increasingmaterial being present in said composition in a ratio of polymericmaterial to cohesion-increasing material of between about 1:6 to about1:1.
 14. A molding material consisting essentially of (1) discrete solidparticles of a thermoplastic polymeric material consisting of poly(vinylacetate) or a copolymer containing at least 60 mole percent vinylacetate, said thermoplastic polymeric material having a particlediameter between about 0.5 micron and about 50 microns, saidthermoplastic polymeric particles being dispersed in (2) a tackifyingcohesion-increasing material whose softening point is at or below roomtemperature, said polymeric material and said cohesion-increasingmaterial being present in said composition in a ratio of polymericmaterial to cohesion-increasing material of between about 1:6 to about1:1.
 15. A process comprising selectively coating onto the surface of asubstrate a composition consisting essentially of (1) discrete solidparticles of a thermoplastic polymeric material consisting of poly(vinylacetate) or a copolymer containing at least 60 mole percent vinylacetate, said thermoplastic polymeric material having a particlediameter between about 0.05 micron and about 50 microns, saidthermoplastic polymeric particles being dispersed in (2) a tackifyingcohesion-increasing material whose softening point is at or below roomtemperature, said polymeric material and said cohesion-increasingmaterial being present in said composition in a ratio of polymericmaterial to cohesion-increasing material of between about 1:6 to about1:1; and heating the coated surface of the substrate for a length oftime at a temperature sufficient to fuse the coating.